Class 8 Direct And Inverse Proportions CBSE Questions & Answers

Class 8 · Direct And Inverse Proportions

This is Mathematics Class 8 Direct and Inverse Proportions CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
12 men can dig 8 meters long trench in a day. How many men should be employed for digging 50 meter long trench of the same type in one day?
  • A
    None of these
  • B
    50
  • C
    25
  • D
    75
    Correct
2
In an army camp, there are 320 soldiers. They have sufficient food for 80 days. If after 20 days, 20 soldiers left the camp, for how many more days will the food last?
  • A
    64
    Correct
  • B
    32
  • C
    48
  • D
    56
3
A journey by bus takes 45 minutes at 40 km/hour. How fast must a car go to undertake the same journey in 25 minutes?
  • A
    None of these
  • B
    72 km/h
    Correct
  • C
    48 km/h
  • D
    36 km/h
4
The cost of 5 metres of a particular quality of cloth is Rs 210. Find the cost of 2 metres of cloth of the same type.
  • A
    Rs 100
  • B
    Rs 90
  • C
    Rs 60
  • D
    Rs 84
    Correct
5
A mixture of paint is prepared by mixing 1 part of red pigments with 8 parts of base. How many parts of base will be used in mixture by mixing 4 part of red pigment?
  • A
    36
  • B
    40
  • C
    32
    Correct
  • D
    28
6
6 pipes are required to fill a tank in 1 hour 20 minutes. How long will it take if only 5 pipes of the same type are used?
  • A
    80 minutes
  • B
    72 minutes
  • C
    56 minutes
  • D
    96 minutes
    Correct
7
Two quantities x and y are said to be in ___________ if they increase (decrease) together in such a manner that the ratio of their corresponding values remains constant.
  • A
    mix proportion
  • B
    direct proportion
    Correct
  • C
    None of these
  • D
    inverse proportion
8
Two quantities x and y are said to be in _________ if an increase in x causes a proportional decrease in y (and vice-versa) in such a manner that the product of their corresponding values remains constant.
  • A
    mix proportion
  • B
    inverse proportion
    Correct
  • C
    direct proportion
  • D
    None of these
9
An electric pole, 14 metres high, casts a shadow of 10 metres. Find the height of a tree that casts a shadow of 15 metres under similar conditions.
  • A
    25 metres
  • B
    21 metres
    Correct
  • C
    None of these
  • D
    30 metres
10
A machine in a soft drink factory fills 840 bottles in six hours. How many bottles will it fill in five hours?
  • A
    1400
  • B
    600
  • C
    None of these
  • D
    700
    Correct
11
Suppose 2 kg of sugar contains \({\text{9 }} \times {\text{ 1}}0{\text{6}}\)crystals. How many sugar crystals are there in 1.2 kg of sugar?
  • A
    None of these
  • B
    5.4 crystals
  • C
    \({\text{5}}.{\text{4 }} \times {\text{ 1}}{0^{\text{6}}}\)crystals
    Correct
  • D
    \({\text{1}}{0^{\text{6}}}\)crystals
12
Two persons could fit new windows in a house in 3 days. One of the persons fell ill before the work started. How long would the job take now?
  • A
    4 days
  • B
    None of these
  • C
    8 days
  • D
    6 days
    Correct
13
The cost of 5 metres of a particular quality of cloth is Rs 210. Find the cost of 4 metres of cloth of the same type.
  • A
    Rs 200
  • B
    Rs 150
  • C
    Rs 180
  • D
    Rs 168
    Correct
14
A mixture of paint is prepared by mixing 1 part of red pigments with 8 parts of base. How many parts of base will be used in mixture by mixing 7 part of red pigment?
  • A
    70
  • B
    63
  • C
    56
    Correct
  • D
    49
15
There are 100 students in a hostel. Food provision for them is for 20 days. How long will these provisions last, if 25 more students join the group?
  • A
    20
  • B
    12
  • C
    16
    Correct
  • D
    18